FIG. 1 illustrates a prior art method of making a semiconductor device including providing a semiconductor device 10 with a first layer 6 such as a dielectric layer having an upper surface 8. A photoresist layer 26 is deposited over the upper surface 8 of the first layer 6 and patterned and a development composition 22 is flowed over the photoresist layer 26 so that individual photoresist features are defined, such as a first photoresist feature 12 and a second photoresist feature 14 with a gap 16 therebetween. The first photoresist feature 12 includes an inside wall 18 facing an inside wall 20 of the second photoresist feature 14. The photoresist features 12 and 14 have an outside wall 19 and 21 respectively. FIG. 2 illustrates a prior art step in the semiconductor manufacturing wherein the development fluid or rinse fluid is spun dry in an effort to leave the individual photoresist features 12, 14. However, the photoresist features 12, 14 can collapse as illustrated in FIG. 2. The collapsing becomes more prevalent in situations where the aspect ratio, that is the photoresist thickness (height)/photoresist width ratio is greater than 3. The collapse problem is also prevalent when small photoresist features such as line widths less than 150 nm are formed.
As will be appreciated from FIG. 2, when the photoresist collapses typically the inner side wall 18 of the first photoresist feature 12 engages the inner side wall 20 of the second photoresist feature 14 to close off the gap 16 that was therebetween. FIG. 4 is a plan illustration of the collapsed photoresist features 12 and 14. It will be appreciated that there is no opening or gap 16 between the first photoresist feature 12 and the second photoresist feature 14 and therefore wet or dry etching materials, or other material cannot pass between the photoresist features.
Messick et al., U.S. Pat. No. 6,451,510, discloses one solution to preventing photoresist collapse. Messick et al. discloses a method of developing photoresist patterns on electronic component substrates such as semiconductor wafers using specially defined developer compositions in sequence with a specially defined rinse composition to develop an exposed photoresist pattern and then the developed pattern is rinsed. Both the developer composition and the rinse composition contain an anionic surfactant and, when these solutions are used in sequence, they form a photoresist pattern which avoids pattern collapse even with small features such as line widths less than 150 nm and with aspect ratios greater than about 3. Disclosed as suitable anionic surfactants are ammonium perfluoroalkyl sulfonate and ammonium perfluoroalkyl carboxylate.
The present invention provides alternatives to the prior art.